1. Technical Field
The present disclosure relates to data processing, and in particular, to data structures.
2. Description of the Related Art
Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
There are a few well known and commonly used data models for structured and semi-structured data; among them are the relational data model and the hierarchical data model. The relational data model forms the basis for modern database technology, and SQL (structured query language) query language is developed and standardized to retrieve/update information stored in the database. Built upon the relational data model and the SQL query language, various ETL (extraction, transformation and loading) tools are developed to transform and integrate data stored in different database systems or flat file formats. On the other hand, databases based on hierarchical data model were popular before relational databases were introduced and hierarchical data structures like IDOC (intermediate document) and EDI (electronic data interchange) have been broadly used to exchange and integrate information among heterogeneous application systems. Today, with the wide acceptance of XML (extensible markup language) technologies and others like JSON (JavaScript object notation) in the internet and cloud computing environment, the hierarchical data model is becoming more and more important. Data transformation and integration tools like SQL/XML (XML extension to the SQL), XQuery and XSLT (extensible stylesheet language transformations) are also developed.